Difference between rectum and colon is that most of the rectum lacks serosa. Thus for the rectum, a T3 is invasion into perirectal fat; for colon, T3 is invasion of serosa. Also for the rectum, T4 is only invasion of other organs, whereas for the colon T4 can also be perforation through serosa.

Comments: Lots of issues - End point survival without looking at local control, RT fields included para-aortic LNs, not sufficient power (accrued 25% patients), high number of ineligible patients (15%), broad eligibility criteria (including low risk T3N1), chemotherapy now outdated, inability in many patients to determine tumor location (no preop imaging, no surgical clips), radial margins often not examined on pathology